Discrimination between glycosylation patterns of therapeutic antibodies using a microfluidic platform, MALDI-MS and multivariate statistics

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2011-2012

This review is the seventh update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2012. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, and fragmentation are covered in the first part of the review and applications to various structural types constitute the remainder. The main groups of compound are oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:255-422, 2017.

N-Glycan profile analysis of transferrin using a microfluidic compact disc and MALDI-MS

It has been known for a long time that diseases can be associated with changes to the glycosylation of specific proteins. This has been shown for cancer, immunological disorders, and neurodegenerative diseases. The possibility of using the glycosylation patterns of proteins as biomarkers for disease would be a great asset for clinical research or diagnosis. There is at present a lack of rapid, automated, and cost-efficient analytical techniques for the determination of the glycosylation of specific serum proteins. We have developed a method for determining the glycosylation pattern of proteins based on the affinity capture of a specific serum protein, the enzymatic release of the N-linked glycans, and the analysis of the glycan pattern using MALDI-MS. All sample preparation is performed in a disposable centrifugal microfluidic disc. The sample preparation is miniaturized, requiring only 1 μL of sample per determination, and automated with the possibility of processing 54 samples in parallel in 3.5 h. We have developed a method for the glycosylation pattern analysis of transferrin. The method has been tested on serum samples from chronic alcohol abusers and a control group. Also, a SIMCA model was created and evaluated to discriminate between the two groups.

Towards real-time monitoring of therapeutic protein quality in mammalian cell processes

Protein biopharmaceuticals are mainly produced in mammalian cells which can perform human-like post-translational modifications crucial to protein function. Subject to high variability, these critical quality attributes should be monitored and controlled during the manufacturing process. However, the large time requirements for analysis have been a bottleneck. Recent advances towards automated and high-throughput techniques, combined with multivariate data analysis, are increasingly providing relevant process knowledge in near real-time. New or re-designed analytical tools suited for monitoring product quality are starting to fit in this landscape. Moreover, omics technologies are expanding our understanding of how intracellular mechanisms and the extracellular milieu influence protein quality and quantity, reshaping the adoption of Process Analytical Technology (PAT) and Quality by Design (QbD) in the biopharmaceutical industry.

Glycosylation profiling of therapeutic antibodies in serum samples using a microfluidic CD platform and MALDI-MS

The serum clearance rate of therapeutic antibodies is important as it affects the clinical efficacy, required dose, and dose frequency. The glycosylation of antibodies has in some studies been shown to have an impact on the elimination rates in vivo. Monitoring changes to the glycan profiles in pharmacokinetics studies can reveal whether the clearance rates of the therapeutic antibodies depend on the different glycoforms, thereby providing useful information for improvement of the drugs. In this paper, a novel method for glycosylation analysis of therapeutic antibodies in serum samples is presented. A microfluidic compact-disc (CD) platform in combination with MALDI-MS was used to monitor changes to the glycosylation profiles of samples incubated in vitro. Antibodies were selectively purified from serum using immunoaffinity capture on immobilized target antigens. The glycans were enzymatically released, purified, and finally analyzed by MALDI-TOF-MS. To simulate changes to glycan profiles after administration in vivo, a therapeutic antibody was incubated in serum with the enzyme α1-2,3 mannosidase to artificially reduce the amount of the high mannose glycoforms. Glycan profiles were monitored at specific intervals during the incubation. The relative abundance of the high mannose 5 glycoform was clearly found to decrease and, simultaneously, that of high mannose 4 increased over the incubation period. The method can be performed in a rapid, parallel, and automated fashion for glycosylation profiling consuming low amounts of samples and reagents. This can contribute to less labor work and reduced cost of the studies of therapeutic antibodies glycosylation in vitro and in vivo.